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C. S. BRAGG ET AL POWER ACTUATOR 7,833

3 Sheets-Sheet 1 Original Filed June 26, 1924 I l-Ill.-

Q x glg mkb A'ITQRNE C. S. BRAGG ET AL POWER ACTUATOR 17833 3 Sheets-Sheet 2 Oct. 21, 1930.

Original Filed June 26 1924 w INVENTOR5 Y m m ATTORNEY C. S. BRAGG ET AL POWER ACTUATOR Re. 17,833

3 Sheets-Sheet 5 Oct. 21, 1930.

7 Original Filed June 26 why 226 Ulla M FEE\ Em \z? Reiuued Oct. 21, 1930 UNITED STATES PATENT orrlce CALEB 8. IBRAGG, 0] ram BEACH, FLORIDA, AND VICTOR- W. KLIESRLTH, OF PORT WASHINGTON, NEW YORK, ABSIGNORS TO BRAGG-KLIESBATH CORPORATION, 0]

LONG ISLAND CITY, NEW YORK, A CORPORATION OF NEW YORK POWER ACTUATOR Original No. 1,592,918, dated July 20, 1928, Serial No. 722,487, filed June 28, 1824s Application for reissue filed December 24, 1927. Serial No. 242,464.

Our inventionconsists in the novel features hereinafter described, reference being had to the accompanying drawings which illustrate several embodiments of the same, selected by us for purposes of illustration, and the said invention is fully disclosed in the following description and claims.

' in carrying out our invention we employ a power actuator especially adapted for use in brake mechanisms for automobiles and particularly with automobiles provided with brakes on all four of the supporting wheels, the actuator being provided with two pistons working in the same cylinder, each of which pistons is operatively connected with the brake mechanism for two wheels, preferably arran ed opposite to each other at the same end 0 the chassis. The pistons are caused to move in the cylinder toward and from each other by establishing differential pressures between that portion of the cylinder between the pistons and the portions at each end of the cylinder on the opposite sides of the piston, and we provide throttling reversing valve mechanism connected with an operator operated device for controlling the movements of said pistons, the valve mechanism being constructed to maintain the pistons in balanced condition at any interjacent position of the valve mechanism between its limits of movement, so that the movements of the pistons and their connected brake mechanisms can be controlled with the utmost delicacy, while the operator is relieved from the exertion of actually operating the brake mechanism. The valve'mechanism is also connected to one of the pistons by means ermitting lost motion, so that in case of ailure of the power, the said piston and its connected brake mechanism may nevertheless be operated directly by the operator. In the application of our improved mecha nism to automobiles in which an internal 7 combustion engine furnishes the propelling ower, the internal combustion engine afords a convenient means of obtaining the difierential ressures required. Thus, in the operation of an internal combustion engine, there is suction produced by the cylinders in drawing in the charges of explosive mixture between the cylinders and the throttle valve which is at its maximum when the engine is throttled down,,and decreases as the throttle is opened. There is also high compression in the cylinders of the engine which is greatest when the throttle is wide open, and decreases as the throttle is closed. Our improved power actuator, can therefore, be readily operated b the suction from the in take manifold as t e low pressure acting on one face of each piston, or by compressed gases from a cylinder of the engine providing the high pressure acting one one face of each piston and atmospheric air as the low pressure acting on the other face of each piston, or compressed gases from a cylinder of the engine may be emplo ed as the high pressure and suction from t e intake manifold may be employed as the low pressure.

Inractice, however, we find it most convement and advantageous to employ the suction from the intake manifold for the low pressure and atmospheric air forthe high pressure, as specificall shown in the accompanying drawings. ur present invention also contemplates means for preventing one of the pistons from movement in the cylinder and thereby holding out of operation the brake mechanism connected therewith, leaving the other piston to operate the brake mechanism connected to it so that in ajfour wheel brake mechanism for example, the operator operated part, as the foot lever, may be operated under normal conditions so as to apply only two of the brakes, as those for the rear wheels, while in an emergency, or when heavy braking action is required, the

locked piston may be released so that both pistons will operate, and simultaneously apply the brakes of all four of the wheels, when required, and under the entire control of the operator. In some instances this may be accomplished by providing mechanical means for locking and unlocking the free piston not under the mechanical control of an operator operated part, and this result may be accomplished in other ways, as by providing an auxiliary valve for closing the communication between the opposite ends of the cylinder at times when only one piston and the brake mechanism connected therewith are to be employed, and by providing means, under the control of the operator, hereinafter described, for effecting the opening of said auxiliary valve when the operation of both pistons and the brake mechanism connected therewith, is required.

Referring to the accompanying drawings,

Fig. 1 is a diagrammatic view representing an automobile provided with four brakes, one for each of the wheels thereof, and having our improved double piston power actuator operatively connected therewith, and with the intake manifold of the engine for supplying the lower pressure for operating the power actuator.

Fi 2 is an enlarged sectional view of the doub e piston power actuator.

Fig. 2 is a detail drawn to an enlarged scale showing the parts at the left of Fig. 2.

Fig. 2 is a section on the line 2"2 of i 3 and 4 are enlarged sectional views of a firm of valve mechanism which may be conveniently employed in connection with the power actuator, showing the valve mechanism in reversed positions.

Fig. 5 is a detail sectional view of a part of a modified form of power actuator, in which an auxiliary valve and operator controlled cam for the same are employed for connecting and disconnecting the opposite ends of the cylinders, to enable the operator to employ one piston and the brake mechanism connected therewith or both pistons and their respective brake mechanisms as re uired.

ig. 6 is a detail view showing another modification of our improved actuator for enabling the operator to operate one or both pistons of the actuator as required.

Referring to the drawings, 1, re resents the power cylinder of our improve power actuator, both ends being closed by suitable heads, indicated at 23, respectively, secured to the c linder by any suitable means, as by connecting bolts and nuts, 4, see Fig. 1. Within the cylinder, 1, is a main double acting piston, indicated at 10, provided with annular gaskets, 11, extending in opposite directions and engaging the inner surface of the cylinder wall. The piston, 10, is provided with a hollow piston rod, 12, which extends through a guiding sleeve 13, bushing, 14, and stuffing box, 15, with which the head, 3, of the cylinder is provided. The cylinder is also provided with a second piston,'10, which we term the auxiliary or floating piston, having similar gaskets, 11, extending in opposite directions, and engaging the inner surface of the cylinder. The piston, 10, is provided with a hollow piston rod, 12, extending through a guiding sleeve, 13, bushing, 14", and stuifing box, 15", with which the head, 2, of the cylinder is provided. The

opposite ends of the cylinder are connected by means of a pipe, or passage, 70, so that one or both of said pistons may be actuated by creating difi'erent pressures in the space, A, between said pistons and the connected spaces, BB at the opposite ends of the cylinder. 16, 16 represents a longitudinally movable valve sleeve extending in opposite directions from the throttling and reversing valve mechanism, which in this instance is located in the hub of the main piston, 10. The piston, 10, is provided with two chambers, indicated respectively at 28 and 30. The chamber, 28,-is'connected by passages, 3940, with the central portion, A, of the cylinder between the pistons, while the chamber, 30, is connected by assage, 36, with the portion, B, in the end 0 the cylinder beyond the piston, 10, which, through the pipe or passage, 70, is connected to the portion, B Within the chamber, 28, is a valve collar,-27, secured to the valve sleeve, which is ground to fit the interior of thechamber, 28, and is movable therein between end washers, 27* and- 27", of leather or other suitable material, thus establishing a limit of lost motion amounting to' substantially of an inch in this particular instance between the valve sleeve and the piston, 10. The portion, 16, of the valve sleeve, also communicates with a plurality of air inlet ports, 25, whichcan be brought into communication with the chamber, 28, when the valve, 27, is in one :extreme position, and can be brought into communication with the chamber, 30, when the valve is in its other extreme position, the said ports, 25, being maintained closed when in an interj acent position between the limits of movement of the valve mechanism. Within the chamber, 30, the valve mechanism is rovided with a collar valve, 29, ground to fit the wall of the chamber and movable within said chamber between end washers, 29 and 29", and the portion,-16, of the valve sleeve is provided with a plurality of suction ports, indicated at 24, which are capable of being brought into communication with the chamber, 30, in one extreme movement of the valve mechanism and into communication with the central space, A, of the cylinder when in the from the intake manifold, 21, of the inter nal combustion engine, 22, of the automobile, which is connected to an inlet port, 20, in the exterior portion of the piston rod, 12, by a flexible connection permitting the necessary movement of the piston, rod. In

order to insure the instantaneous operation of the brake mechanism without interference I with idling of motor, etc., we prefer to interpose a vacuum tank between the intake manifold and the actuator, and in Fig. 1, we have shown such atank at 23, connected by a pipe, 23, with the intake manifold, said ipe bein preferably provided with a reguiiiting va ve, 23, adjacent to the manifold, and a check valve, 23", adjacent to the tank. A flexible pipe, 23, which may be of considerable diameter, extends from the tank, 23", to the port, 20. Communication between the port, 20, and the low pressure ports, 24, is established through the hollow piston rod, 12", and the movable valve sleeve section, 16. In order to further provide for cutting off the suction when the pistons are in retracted ositions, which is the normal or off positlon of the pistons, as indicated in Fig. 2, we prefer to provide the hollow piston rod, 12, with a plug or partition, 18, permanently secured therein adjacent to the port, 20, and provided with an axial aperture, 18", and a valve seat, 18, as best shown in Fig.2. We also provide a valve, 18, for engaging the valve seat, 18,

when the parts are in normal or-oif'position, said valve being secured to a rod, 9, extendin through the hollow rod and being connected to the sleeve section, 16, by means providing lost motion, in this instanceha wrist pin, 19, on the rod, 9, engaging a.

slot, 19, in the sleeve section. When the pistons move away from each other and return to normal or retracted positions, as shown in Fig. 2, the wrist pin, 19, will be engaged by the end of the slot, 19, in the sleeve, 16', and this will draw the valve,-18, firmly uponits seat and form an additional sealing means, when the ,parts are not in operation. moved in the direction of the arrow in Fig. 2, the end of slot, 19, relieves the wrist pin,

19, and permits the valve, 18, to open by suction, and it will be assisted in opening by the frictional engagement between the -valve sleeve, 16, and the wrist pin. The

valve, 18, will remain open until it is closed by the return of the pistons and valve sleeve, 16, to normal or retracted positions. The slot, 19, permits the valve sleeve to move in the direction of the arrow in Fig. 2, to a greater or less extent as required, without interference from the valve rod, 9.

The higher pressure fluid in this instance is atmospheric air, which is admitted to the interior of the valve sleeve section, 16,

. through a port or opening, 43, at the outer end of the valve sleeve section, and preferably provided in a plug, 41, screwed into the outer end of the hollow piston rod, 12, and provided with perforated cars, 42, by which it is connected to one pair of brake mechanisms, asthe brakes for the rear wheels of the automobile. The outer end When the valve sleeve, 16", is

of the other piston rod, 12", is provided with similar ears, 42, by'which it is connected to the remaining brake mechanisms, as the brakes for the front wheels. In the present instance as shown in Fi 1, the piston rod, 12, is connected b a lini, 63, with an arm, 64, on a rock sha t, 59, provided with arms, 58, each of which is connected by a link, 57, to an arm, 56', for rotatin forwardly a cam, 55, of one of the rear w eel brake mechanisms, which in this instance, is shown as comprising brake drums, 52, and separable braking shoes, 53, pivoted at 54,-and provided with the usual retracting springs, 61. It is to be understood, further, that the particular form of brake mechanism and its connections with the actuator form no-part of our present invention. The piston rod, 125, is connected in a similar manner with the brake mechanisms for the forward wheels and-the various parts of the brakes and connecting mechanisms are indicated by similar numerals.

50 represents the operator operated part which in this instance is the usual foot lever pivoted to the chassis and provided with a retracting. spring, 51. T1115 lever is connected to thelongitudinally movable valve sleeve, ,16, 16, and the throttling and reversing valve mechanism by any usual or desired means. In the present instance we have shown the lever, 50, connected by a link rod, 62, with a rectangular frame comprising longitudinally movable slide rods, 71, engaging guiding apertures, 72, in parts secured to the cylinder heads and projecting therefrom, said rods being connected at their forward ends by cross rod, 73, extending around the piston rod, 12", and being provided at their rear ends with a cross rod, 4, which extends through a slot, 75, in the piston rod, 12, and engages suitable apertures, in the sleeve, 16, so that the sleeve and valve mechanism, including the collar valves, 27 and 29, may be shifted longitudinally with respect to the piston, 10, by the opera tion of the foot lever, and in the reverse direction by the retracting spring, 51.

In the operation of the apparatus, as shown in Figs. 1, 2, 3 and 4 of the drawings, when it is desired to apply the brakes, the operator will depress the foot lever, 50, thereby shifting the sleeve, 16, and the reversing valve mechanism in the direction of the arrow in Fig. 2. This releases the valve, 18, from the retaining action of the rod, 9, and permits the valve to be opened by the suction, and simultaneously moves the low pressure ports, 24, into communication with the central space, A, of the actuator cylinder, and the high pressure ports, 25, .into communication with the chamber, 30, as indicated in Fig. 3. The suction of the engine maintains a partial vacuum at all times in the suction tank and air will be immediately exhausted from the 30 thechamber, 30, and the high pressure ports,

central space, A, of the cylinder, while atmospheric air will be admitted through the high pressure ports, '25, the passage, 36, and connecting pipe or passage, 70, to both ends of the cylinder, so that the pistons, and 10, will move simultaneously toward each other and thereby simultaneously apply all four of other so that the brake mechanism can be applied with the same accuracy and delicacy of adjustment that is obtained with the usual foot operated brake mechanism, except that the operator is relieved from the exertion necessary to actually apply the brakes. When the operator releases the pedal, 50, it will be moved in the opposite direction, by spring,

51, thereby shifting the valve sleeve and reversing valve mechanism so as to place the low pressure ports, 24, in communication with 25, in communication with the passages, 39 and 40, leading to the space, A, between the pistons. The result of this will be to exhaust the air rapidly from the portions, BB of the cylinder and admit air to the central portion between the pistons which move away from each other and simultaneously release both sets of brakes. The movementof the piston, 10, is limited by the engagement of the hub (which is provided with a packing ring, 76, surrounding the piston rod, 12) with the head, 3, of the cylinder and the return movement ofthe piston, 10, is likewise limited by a projecting sleeve, 77, surrounding the piston rod, 12, and adapted to engage the other head, 2, of the cylinder, the said pistons being limited in order to prevent injury to their gaskets. As the pistons return to their normal positions the end of the slot, 19, in the valve sleeve, 16, will engage the wrist pin, 19, and exert a'draw on the rod, 9, thereby drawing the valve, 18, firmly upon its seat and retaining it in closed position to assist in sealing the cylinder until the foot lever is again operated. The movement of the pistons toward each other will normally be limited by the application of the brakes. Should pedal, 50, is actuated with suflicient pressure to bring the collar valves, 27 and 29, against the ends of the chambers, 28 and 30, the operator can apply his physical force through the brake pedal and the valve mechanism to the piston, 10, to further apply the brakes connected therewith by hisphysical force, and in case otfailure of power the movement of the valves to this position, in taking up the lost motion between the operator operated part and piston, 10, would automatically vent the cylinder, by connecting it on both sides of the piston with the atmosphere, and the operator can then apply his physical force through the brake pedal and valve mechanism to directly move the piston, 10, and apply the brakes connected therewith by direct physical force of the operator, thereby preventing what otherwise might result in an accident. It is also to be noted that in the operation of our improved brake mechanism, by means of the herein described power actuator, the operator operates the brake pedal in exactly the same manner as to direction of movement and extent of movement as is usual in installations where the power is applied wholly by the operator so that it is unnecessary for the operator to learn a new mode of operation, while at the same time the brakes may be applied and released by the power actuator without any further exertion on the part of the operator than is requiredto move the brake pedal and connected valve mechanism against the pressure of the retracting spring.

Our invention also contemplates, as before stated the employment of means whereby one of the pistons, as the auxiliary or floating piston, 10, may be permitted to remain stationary while the main piston is operated, thereby eilecting the operation of one set of brakes, only, and for releasing the said auxiliary or floating piston, to secure the simultaneous operation of. the brake mechanismsconnected with both pistons when required under the control of the operator. This is particulary advantageous in connection with an automobile having four wheel brakes as it enables the operator to apply the brakes of two wheels, as the rear wheels, under ordinary working conditions, and also to bring into action the brakes of all four wheels in any emergency, or when it is desired to make a sudden stop, or when additional braking power is required, as on very steep hills. In Fig. 5 we have shown a portion of the cylinder ,0 the actuator, at 101, and the pistons are indicated at 110*, respectively, it being understood that the parts of the actuator which are given the same reference numerals, with'lOO added, are constructed in the same manner as is illustrated in Fig. 2 and hereinbefore described, except as hereinafter indicated. represents the pipe or passage, connecting the end portions,

ill)

a valve casing,

the valve, 181, being in close B'*' of the cylinder, the central portion between the pistons being indicated at A The pipe or passage, 170, is provided with indicated at 180, containing a spring actuated valve, 181, for closing the pipe or passage, 170, the said'valve being normally held in closed position by a spring, 182, and being provided with a stem, 183, projecting from the valve casing into posi tion to be engagedby a cam, 184:, carried by one of the slide rods, 171, for actuating the valve sleeve, in the manner indicated in Fig. 2. The valve casing, 180, is provided with a partition, 185, interposed between the sections of the pipe, or passage, 170, leading from said valve to the opposite ends of the cylinder, 101,respeotively, and is provided with a valve seat for the valve, 181. This valve is so located with respect to said seat that it will open against the tension of the spring, 182, when the portion, B of the cylinder to the right of piston, 110, is connected with the source of lower pressure, (as the intake manifold of the engine by the valve mechanism of the actuator), while the light spring will maintain the valve normally in closed position at other times, except when the valve is positively opened by the cam, 184. The cam, 184, is preferably of substantially the same length as the stroke of the pistons, and is preferably adjustable on the rod, 171, so as to permit a certain amount of movement of said rod, su fiicient-to shift the valve mechanism of the actuator and secure effective operation of the main piston, 110, without engaging the stem, 183, of the valve, 181, with the cam, 184. The operator can therefore actuate the brake lever so as to secure the operation of the main piston, 110, and the brake mechanism (as the rear wheel brakes) operatively connected therewith, without producing efi'ective movement of the auxiliary or floating giston, 110, as

position, cuts oil the space, B, of the cylinder from the space, 13 and therefore atmospheric air cannot pass from the space, E, to the space, B and the piston, 110, will, accordingly be held from movement in the cylinder to permit the operation of the other piston and the brake mechanism connected therewith without operating the brake mechanism connected with piston, 110, so held from brake lever to of the actuator cylinder,

movement. If it is required to operate all of the brakes, the operator can depress the a further extent, thus moving the slide rods far enough to bring the cam, 184, into contact with the stem, 183, of the valve, 181, and opening said valvu. This establishes communication for atmospheric air between the end spaces, B B,

and permits piston, 110, to move inwardly toward the other piston, 110, and applies the brake mechareference numerals with 200 nisms, connected therewith, thus ap lying all the brakes, as the front wheel rakes and rear wheel brakes. If the brake pedal is so actuated as to operate both plstons and set the brakes connected therewith, on the release of the brake pedal, the reversing valve will be shifted with respect to the ports of the main piston, 110 thus connecting the suction tank with the end portion, B of the cylinder, while the central portion, A is connected with the atmosphere. The air will be exhausted .from the end portions, B B both pistons will be returned to their normal positions, as the valve, 181, will be held open, as long as thecam, 184, remains in engagement with its stem, and after the cam releases the valve stem, the valve, 181, will be kept open by the suction against the action of its spring until the auxiliary or floating piston is fully returned to its normal position. The operator can, therefore, operate the brake pedal under ordinary conditions without bringing the cam, 184, into engagement with the valve, 181, to ap ly and release only the rear wheel brakes, but can instantly secure the operation of all the brake mechanisms controlled by both pistons by depressing the brake pedal sufliciently to bring the cam, 184, into operative engagement with the stem of the valve, 181, and opening said valve.

In Fig. 6 we have shown another modification of our improved actuator by means of which either one or both of the pistons may be operated as desired, under the control of the operator. In this figure, the parts are also constructed as shown in Fig. 2, except as hereinafter noted, and are given the same added. In this figure, the piston rod, 212, connected with the floating piston, is provided with a groove or recess, 280 adapted to be engaged by a rounded spring detent, 281, mounted in a recess, 282, in the sleeve, 213", of the actuator cylinder, 202, and provided with a spring, 283, held in position by a screw plug, 284, screwed into the recess, 282, by means of which the tension of the spring may be adj usted. The engagement of the detent, 281, with the recess 280, in the piston rod, 212, is such that the auxiliary or floating piston, 210, will be normally heldagainst movement when the valve mechanism of the actuator is moved into position to connect the central portion of the actuator cylinder with the suction, thus permitting the main piston connected with the valve sleeve, here indicated at 216*, to be actuated in either direction to appkly and release the brakes connected therewit In case more than normal braking is re- ,quired, a further depression of the brake pedal suflicient to actuate the valve sleeve, 216, to its full extent (piston, 210, being of the cylinder and a arrested by the resistance of the applied brake mechanism connected therewith) will increase the suction within the central space, A, in the cylinder between the pistons. When the suction has increased sufliciently to enable the piston, 210, to overcome the retarding influence of the detent, the latter will yield and be forced downward against its retracting spring, thus permitting the floating piston,

210, to move inwardly and apply the brake mechanism connected therewith, as the front wheel brakes. When the reversing valve mechanism is shifted in the opposite direction by the brake pedal under the action of its retracting spring, both pistons will return to their normal position, and as soon as the auxiliary or floating piston, 210*, is moved far enough to bring the groove or recess, 280, into engagement with the detent, 281, the latter will spring into place and again lock theauxiliary piston. This construction, will, therefore, enable the operator to actuate one of said pistons, and the brake mechanism connected therewith, as the brakes for the rear wheels, or both'pistons, and the brakes for all four wheels, as may be required.

The form of our invention illustratedin Fig. 6 is not specifically claimed herein, this embodiment being specifically claimed in another application for Letters Patent of the United States filed by us January 31, 1925, and given Serial No. 5,498, the said application being a division of this application, and since issued as Letters Patent No. 1,592,919, granted July 20, 1926.

What we claim and desire to secure by Letters Patent is 1. The combination of a power actuator comprising a cylinder closed at each end, two pistons movable independently of each other in both directions in said cylinder, the said cylinder being provided with a communicating-passage connecting the opposite end portions of the cylinder on the outer faces of the pistons, means for establishing difierential pressures within the central portion of the cylinder between said pistons and within said connected end portions, including a single throttling and reversing valve mechanism constructed to. maintain said pistons in a balanced condition when the reversing valve mechanism is in an interjacent position between its limits of movement, an operator operated part connected with said valve mechanism, and brake mechanisms operatively connected with said pistons.

2. The combination of a power actuator comprising av cylinder closed at each end, two pistons movable independently of each other in both directions in said cylinder, the said cylinder being provided with a communicating passage connecting the opposite end portions of the cylinder on the outer faces of the pistons, means for establishing differential pressures within the central portion of the cylinder between said pistons and within said connected end portions, including a single throttling and reversing valve mechanism constructed to maintain said pistons in a balanced condition when the reversing valve mechanism is in an interjacent position between its limits of movement, an operator operated part connected with said valve mechanism, brake mechanism operatively connected with one of said pistons, and separate brake mechanism operatively connected with the other piston.

3. In a four wheel brake mechanism for automotive vehicles, the combination with a power actuator, comprising a cylinder, a pair of double acting pistons located therein, a communicating passage connecting the end portions of the cylinder on the outer faces of the pistons, means for establishing a difierential of pressures within the central portion of the cylinder between said pistons and within said connected end spaces, including a single throttlingand reversing valve mechanism constructed to maintain said pistons in a balanced condition when in interjacent position between the limits of movement of said valve mechanism, brake mechanism for the non-steering wheels connected with one of said pistons, brake mechanism for the steering wheels connected with the other piston, and anoperatoroperated device connected with said valve mechanism.

4. The combination with a power actuator comprising a cylinder, a pair of double acting pistons working therein, said. cylinder having a communicating passage connecting the end portions of the cylinder on the outer faces of said pistons, means for establishing a differential of pressures within the central portion of the cylinder between said pistons and within said connected end portions, ineluding. a single throttling and reversing valve mechanism constructed to maintain said pistons in balanced condition when the valve mechanism. is in an interjacent position between the limits of its movement, brake mechanism connected with each of said pistons, and an operator operated part connected to saidreversing valve mechanism, said valve mechanism being provided with a movable part connected with one of said pistons by means providing lost motion, whereby on the failure of power, said pis-. ton may be directly actuated by said operator operated part.

5. The combination of an actuator comprising a cylinder closed at its ends, a pair of double acting pistons in said cylinder, said cylinder beingprovided with a communicating passage connecting the end portions on the outer faces of said pistons.

means for establishing diiferential pressures,

in the central portion of the cylinder between said pistons and the said connected end portions, including reversing valve mechanism located in one of said pistons, said valve mechanism including a part connected with the said piston by means permitting lost motion, a hollow piston rod connected with said main piston and extending through the adjacent end of the cylinder, an independent piston rod connected to the otherpiston and extending through the adjacent end of the cylinder, a longitudinally movable valve seeve connected with the movable'part of said reversing valve and having portions extending longltudinally through both of said hollow piston rods, brake mechanism connected with each of said piston rods, an operator operated part, and connections therefrom to said sleeve, and a retracting spring for said operator operated part;

6. The combination with a power actuator, comprising among its members, a power cylinder closed at both ends, a pair of double acting pistons in said cylinder, said cylinder being provided with a communicating passage for connecting the end portions of the cylinder on the outer faces of said pistons, a hollow piston rod extending through one end of the cylinder and connected to one of said pistons, and provided with an inlet aperture, a longitudinally movable reversing valve sleeve extending through said piston and the hollow piston rod thereof, and provided with separated ports, certain of said ports being connected to said inlet aperture, and other ports separated therefrom being adapted to be connected to an outlet passage from said cylinder, said piston being provided with ports and passages for connecting either of said separated ports with the portion of the cylinder between the pistons and the connected portions of the cylinder at the opposite ends thereof, valves carried by said sleeve for controlling said piston ports and sleeve ports. and adapted when in an interjacent position between the limits of movement of said sleeve with respect to saidpiston to-maintain the pistons in balanced condition, a piston rod connected with the other of said pistons, brake mechanisms connected with said piston rods, an operator operated part, and connections between the same and said sleeve.

7. The combination with a power actuator, comprising among its members, a power cylinder closed at both ends, a pair ofdo-uble. acting pistons in said cylinder, said cylinder being provided with a communicating passage for connecting the end portions of the cylinder on the outer faces of said pistons. a hollow piston rod extending through one end of the cylinder and connected to one of said pistons, and provided with an inlet aperture, a longitudinally movable reversing valve sleeve extending through said piston and hollow piston rod thereof, and provided with separated ports, certain of said 06 ports being connected to said inlet aperture,

and other ports separated therefrom being adapted to be connected to an outlet passage from said cylinder, said piston being provided with ports and passages for connecting either of said separated ports with the portion of the cylinder between the pistons and the connected portions of the cylinderat the opposite ends thereof, valves carried by said sleeve for controlling said piston ports and sleeve ports, and adapted when in an interjacent position between the limits of movement of said sleeve with respect to said piston to maintain the pistons in balanced condition, a hollow piston rod connected with the other of said pistons, brake mechanisms connected with said piston rods,

said sleeve extending longitudinally through the hollow piston rod of the other piston and said latter piston rod being provided with an outlet aperture adapted to communicate with said sleeve, an operator operated part, and connections therefrom to said sleeve for actuating the valve mechanism.

8. The combination with a power actuator, I

comprising among its members, a power cylinder closed at both ends, a pair of double acting pistons in said cylinder. said cylinder being provided with a communicating passage for connecting the end portions of the cylinder on the outer faces of said pistons,-

a hollow piston rod extending through one end of the cylinder and connected to one of said pistons, and provided with an inlet aperture, a longitudinally movable reversing Valve sleeve extending through said piston and the hollow piston rod thereof, and. provided with separated ports. certain of said ports being connected to said inlet aperture. and other ports separated-therefrom being adapted to be connected to an outlet passage from said cylinder, said pistons being provided with ports and passages for connecting no i with said piston rods, an operator operated I part, connections therefrom to said sleeve 1neluding a part passing through one of said hollow piston rods, said piston rod being longitudinally slotted to permit of the movement of said connecting part with respect thereto.

9. The combination with a power actuator comprising a cylinder, a pair of double acting pistons movable therein, said cylinder being provided'with a communicating passage connecting the end portions of the cylother piston, an operator operated device connected with said reversing valve mechanism, and means for holding one of said pistons from movement in the cylinder while permitting the operation of the other piston and the brake mechanism connected therewith without operating the brake mechanism connected with the piston so held from movement. v

10. The combination wit-ha power actuator comprising a cylinder, a} pair of double acting pistons movable therein, said cylinder being provided with a communicating passage connecting the end portions of the cylinder on the outer faces of said pistons, means for establishing difl'erential pressures in the central portions of the cylinder between said pistons and said connected end portions, including reversing valve mechanism constructed to maintain said pistons in balanced condition when in an interjacent position between the limits of movement of the valve mechanism, brake mechanism operatively connected with one of said pistons, independent brake mechanism connected with the other piston, and an operator operated part for efiecting the operation by power of one of said pistons and the brake mechanism connected therewith or both of said pistons and their connected brake mechanisms simultaneously, as required.

11. The combination with a power actuator comprising a cylinder, a pair of double acting pistons movable therein, said cylinder being provided with a communicating passage connecting the end portions of-the cylinder on the outer faces of said pistons, means for establishing differential. pressures in the central portion of the cylinder between said pistons and said connected end portions,

including reversing valve mechanism constructed to maintain said pistonsin balanced condition when in an interjacent position between the limits of movement of the valve mechanism, brake mechanism operatively erator operated part for holding said auxiliary valve in open position to effect the simultaneous actuation of both pistons and their connected brake mechanisms.

' 12. The combination with a power actuator comprising a cylinder, a pair of double acting pistons movable therein, said cylinder being provided with a communicating passage connecting the end portions of the cylinder on the outer faces of said pistons, means for establishing differential pressures in the central portion of the cylinder between said pistons and saidconnected end portions, including reversing valve mechanism constructed to maintain said pistons in balanced condition when in an interjacent position between the limits of movement of the valve mechanism, brake mechanism operatively connected with one of said,pistons,

independent brake mechanism connected with the other pistons, a normally closed spring actuated auxiliary valve located in the communicating passage between the ends of the cylinders and'adapted to be opened automatically against the action, of its spring when the reversing valve is in one position, a movable cam for opening said auxiliary valve and holding it in open position, an operator op erated device, and connections therefrom to i said reversing valve and to said cam.

mechanism, brake mechanism operatively connected with one of said pistons, independent brake mechanism connected with the other piston, a normally closed spring actuated auxiliary valve located in the communicating passage between the ends of the cylinders and adapted to be opened automatically against action of its spring when the reversing valve is in one position, an operator operated device, connections therefrom to said reversing valve, and an adjustable cam connected with said operator operated device for actuating said auxiliary valve to open the same, said cam being normally out of operative relation with said aux: iliary valve and permitting the operation of said reversing valve without bringing the cam into operative relation with the said auxiliary valve.

14. The combination with a power actuator comprising a cylinder, a pair of double acting pistons movable therein, said cylinder er on the outer faces 0 said pistons, means for establishing diflerential pressures in the central portion of the cylinder between sa d pistons and said connected end portions,.1n-

eluding reversing valve mechanism constructed to maintain said pistons in balanced condition when in an interjacent position between the limits of movement of the valve mechanism, brake mechanism operatively connected with one of said pistons, independent brake mechanism connected with the other piston, a normally closed spring actuated auxiliary valve located in the communicating passage between the ends of the cylindersand adapted to be opened automatically against the action of its spring when the reversing valve is in one position, an operator operated part, operative connections therefrom to said reversing valve mechanism, including a longitudinally movable rod, and a cam for actuating said auxiliary valve to open the same, adjustably secured to said rod and normally out of operative relation with said auxiliary valve.

15. The combination of a power actuator, and means for connecting it with sources of higher and lower pressures, including a single controlling valve mechanism, means for connecting said actuator with independently operable brake mechanisms for a plurality of pairs of wheels of the vehicle for operating all of said vbrake mechanisms by power, under the control of said valve mechanism, an operator operated part operatively connected with said valve mechanism, and through the same to certain of said brake mechanisms less than the whole number operatively connected with the actuator, to enable the operator to apply his physical force to the brake mechanlsms only connected with the operator operated part in addition to the power of the actuator, or to operate said last mentioned brake mechanisms by physical force alone in case of failure of power.

16. The combination of a power actuator, and means for connecting it with sources of higher and lower ressures, including a single controlling vave mechanism, means for connecting said actuator with independently operable brake mechanisms for a plurality of pairs of wheels of the vehicle for operating all of said brake mechanisms by power, under the control of said valve mechanism, an operator operated part operatively connected with said valve mechanism, and connections from portions of the valve mechanism connected with said operator operated part to certain of said brake mechanisms less than the whole number operatively connected with the actuator, to enable the operator to apply his physical force through said valve mechanism only to the brake mechanisms so connected with the operator operated part, in

17. The combination of a power actuator, and means for connecting It with sources of higher and lower pressures, including a single controlling valve mechanism, means for con-. necting said actuator with independently op erable brake mechanisms for a plurality of pairs of-wheels of the vehicle, including the steering wheels for applying all of said brake mechanisms by power, under the control of said valve mechanism, anoperator operated part operatively connected with said valve mechanism, and through the same to the brake so I mechanisms for the non-steering wheels, to enable the operator to apply his physical force to the brake mechanisms for the nonsteering wheels only, in addition to the power of the actuator or in-case of failure of power.

18. The combination of apower actuator, and means for connecting it with sources of higher and lower pressures, including a single controlling valve mechanism, means for connecting said actuator with independently operable brake mechanisms for a plurality of pairs of wheels of the vehicle,-including the steering wheels for applying all of said brake mechanisms by power, under the control of v i 5 sald valve mechan1sms, an operator operated 9 part operatively connected with'said valve mechanism, and connections from portions of said valve mechanism connected with said operator operated part to the brake mecha-. nisms for the non-steering wheels only, to enable the operator to apply his physical force through said valve mechanism to the brake mechanisms for the non-steering wheels, in additionvto the power of the actuator or in case of failure of power. i

19. The combination of a power actuator comprising a cylinder closed at each end, two pistons movable independently of each other, in both directions in said cylinder, the said cylinder being provided with a communicating passage connecting the opposite end portions of the cylinder on the outer facesof the pistons. means for establishing difl'erential pressures within the central portion of the cylinder between said pistons and within the connected end portions thereof, including a single reversing valve mechanism constructed to maintain said pistons in a balanced cond1- tion when the reversing valve mechanism is other being connected with said operator operated part.

20. The combination of a power actuator comprising ac linder closed at each end, two pistons movable independently of each other in both directions in said cylinder, the saidcylinder being provided with a communicating passage connecting the opposite end ortions of the cylinder on the outer faces 0 the pistons, means for establishing difierential pressures within the central portion of'the cylinder between said pistons and within the connected end portions thereof, including a single reversing valve mechanism constructed to maintain said pistons in a balanced condition when the reversing valve mechanism is in an interjacent position between its limits of movement, an operator operated part connected with said valve mechanism, brake mechanism operatively conected with one of said pistons, and independent brake mechanism independently connected with the other piston, said valve mechanism including a valve casing and a valve actuating member movable with respect to each other, one of said relatively movable parts being connected with one of said pistons, and the other being connected with said operatoroperate d part,

and means for limiting the relative movement between the said parts of said valve mechanism. to enable the operator to apply his physical force to the brake mechanism only connected with the said piston to which the said portion of the valve mechanism is connected, in addition to the power of the actuator, or in case of failure of power.

21. The combination of a power actuator comprising a cylinder closed at each end, two pistons movable independently of each other, in both directions in said cylinder, the

said cylinder being provided with a communicating passage connecting the opposite end ortions of the cylinder on the outer faces of t e pistons, means for establishing differential pressures within the central portion of the cylinder between said pistons and within the connected end portions thereof, in-

cluding a single reversing valve mechanism constructed to maintain-said pistons in a balanced condition when the reversing valve mechanism is in an interjacent position be tween its limits of movement, brake mechanisms for the steering wheels of-the vehicle connected with one of said pistons, brake mechanisms for non-steering wheels of the vehicle connected with the other of said pistons, said valve mechanism including a valve casing and a valve actuating part movable with respect to each other, one of said rela tively movable parts being connected with the brake mechanism for the non-steering wheels, and the other being connected with said operator operated part, and means for limiting the relative movement of said relatively movable parts to enable the operator to asingle controlling valve mechanism, means 7 for connecting said actuator with independently operable brake mechanisms for a plurality of pairs of wheels of the vehicle, for applying all of said brake mechanisms by power under the control of said valve mechanism, an operator operated part, and connections from said operator operated part to certain of said brake mechanisms less than the whole number operatively connected with said actuator and serving to operate said valve mechanism, to enable the operator to apply his physical force to the brake mechamsms only connected with said operator operated part, in addition to the ower of the actuator or in caseof failure 0 power. 23, In an automotive vehicle provided with an internal combustion engine having a throttle controlled suction passage, the combination of a power actuator and means for connecting it with said suction passage and with a source of higher fluid pressure, including a single controlling valve mechanism, means for connecting said actuator with independently operable brake mechanisms for a plurality of pairs of wheels of the vehicle includin the steering wheels, for applying all of sai brake mechanisms by power under the control of said valve mechanism, an operator operated part, and connections from said operator operated part to the brake mechanisms for non-steering wheels and serving to actuate said valve mechanism, to enable the operator to apply his physical force to the brake mechanisms for the non-steering wheels only, in addition to the power of the actuator or in case of failure of power.

24,. In an automotive vehicle provided with an internal combustion engine having a throttle controlled suction passage, the combination of a power actuator and means for connecting it with said suction passage and with a source of higher fluid pressure, including a single controlling valve mechanism, means for connecting said actuator with independentlv operable brake mechanisms for a plurality of pairs of wheels of the vehicle including the steering wheels, for operating all of said brake mechanisms by power under the control of said valve mechanism, an operator operated part operatively connected with said valve mechanism, and connections from portions of said valve mechanism connected to said operator operated part to the brake mechanism for non-steering wheels, to en- 'able the operator to apply his physical force to the bra e mechanisms for the non-steering wheels only, in addition to the power of the actuator or in case of failureof ower.

25. In an automotive vehic e rovided 'withan internal combustion engine aving a throttle controlledsuction passage, the cominder on the outer faces of the pistons, means for connecting the central portion of the cylinder between said pistons and said connected end portions of the cylinder, with said suction passage and with a source of higher pressure, including a single reversing valve mechanism constructed to maintain said pistons in a balanced condition when the re- I versing valve mechanism is inan interjacent position between its limits of movement, an operator operated partconnected with said valve mechanism, and brake mechanism operatively connected with said pistons.

26. In an automotive vehicle provided with an internal combustion engine having a throttle controlled suction passage, the combination of a power actuator comprising a cylinder closed at each end. two pistons movable independently of each other, in both directions in said cylinder, said cvlinder being provided with a communicating passage connecting the opposite end portions of the cylinder on the outer faces of the pistons. means for connecting the central portion of the cvlinder between said pistons and said.

connected end portions of the cylinder, with said suction passage and with a source of.

higher pressure, including a single reversing valve mechanism constructed to maintain said pistons in a balanced condition when the reversing valve mechanism is in an interj acent position between its limitsof movement, an operator operated part connected with said valve mechanism, separate brake mechanisms operatively connected with each of said pistons, and connections from portions of the valve mechanism connected with said operator operated part to certain of said brake mechanisms less than the whole number, to enable the operator to apply his physi- 'cal force through said valve mechanism to the brake mechanism only connected with the operator operated part, in addition to the ower of the actuator or in case of failure of Dower.

27. In an automotive vehicle-provided with an internal combustion engine having a throttle controlled suction passage, the combination of a power actuator comprising a cylinder closed at each end, two pistons movable independently of each other, in both directions in said cylinder, .said cylinder beconnecting the opposite end nism, brake mechanism operatively connected with one of said pistons, independent brake mechanisms connected with the otherof saidpistons, said operator operated part being operatively connected with the brake mecha-' nisms which. are connected'to' the piston in which said valve mechanism is located, to enable the operator to apply his physical.

force to said brake mechanisms only, in addition to the power of the actuator or-in case of failure of power. i

' 28. In an automotive vehicle provided with an internal combustion engine having a throttle controlled suction passage, the combination of a power actuator comprising a cylinder closed at each end, a main piston and an auxiliarv piston both movab e in both directions in said cylinder, said cvlinder being provided with a communicating passage connecting theopposite end portions of the cylinder on the outer faces of the pistons. means for connecting the central nortionof the cylinder between said pistons and said pairs of wheels of the vehicle including the steering wheels connected with said pistons, and operative connections from the operator operated part to the brake mechanisms for the non-steering wheels only, to enable the operatorto apply his. physical force to the brake mechanisms for the non-steering wheels in addition to the powerof the actuator or in case of failure of power.

29. In an automotive vehicle provided with an internal combustion engine having a throttle controlledsuction passage, the combination of a power actuator comprisinga cylinder closed at each end, two pistons movable independently of each other, in both directions in said cylinder, said cylinder being provided with a communicating passa e connecting the opposite end portions of t e cylinder on the outer faces of the pistons, means for connecting the central portion of the cylinderbetween said pistons and said connected end portions of the cylinder, with said suction passage and with a source of higher pressure, including a single reversing valve mechanism located in one of said pistons and constructed to maintain said pistons in a balanced condition when the reversing valve mechanism is in an interjacent position between its limits of movement, an operator operated part connected .with said valve mechanism, independently operable brake mechanisms for a plurality of pairs of wheels of the vehicle, including the steering wheels, and operative connections from portions of Y said. valve mechanism connected to said operator operated .part to the brake mechanisms for the non-steering wheels only, including a provision for lost motion sufii cient to insure the operation of said valve mechanism, to

enable the operator to ap ly his physical force through said valve mec anism to the brake mechanisms for the non-steering wheels, or in end portions of the cylinder, with said suction. passage and with a source of-higher' pressure, includinga single reversing valve mechanism constructed to maintain said pistons in a balanced condition when the reversing 'valve' mechanism is in an interjacent position between its limits 7 of movement, an o erator operated part connected with sai valve mechanism, brake mechanisms: operatively 7 ing connected with connected with said pistons, said valve mechanism comprising a valve casing and a valve actuating part movable. relatively to said casing, one 0 said relatively movableparts besaid operator operated P mi 31. In an automotive vehicle provided with an internal combustion engine having athrottle controlled suction passage,-the combination of apower actuator comprising a c linder closed at each end, twopistons mova le independently of each other, in both directions in said cylinder, said cylinder being provided with a communicating passage connecting the opposite end portions of the cylinder on the outer iaces of the pistons, means for connecting the central portion of the cylinder between said pistons and said connected an automotive vehicle 'provided' with an internal combustion engine having the pistons, means end portions of the cylinder, with said suction passage and with a source 0 higher pressure includlng a single reversing valve mechanism located in one of sa1d pistons and constructed to maintain said pistons in a balanced condi-" tion when the reversing valve mechanism is in an interjacent position between its limits of movement, an operator operated part connected with said valve mechanism, brake mechanism operatively connected with the piston in which said valve mechanism is 10- Y cated, independent brake mechanism indepistons, said valve mechanism including a valve casing and a valve actuating part movable relatively to the casing, one of said relatively movable parts being connected to the said pistons onlyjinwhich said valve mechap'endently connected with the other of said nism is located, and the other being connected .With said operator operated part, and means for limiting the relative movement between i said parts of said valve mechanism, to enable the operator to apply his physical force to the brake mechanismonly connected with the said piston to which the said portion of the valve mechanism is vconnected, in addition tothe power of the actuator or in case of failure of power.

32'. In an automotive vehicle provided with an internal combustion engine having a throttle controlled suction passage, the combination of a power actuator comprising a cylin der closed at each end, two pistons movable independently of each other in both directions in said cylinder, said cylinder being provided with a communicating passage connecting the opposite end portions of the cylinder' on the outer faces of the pistons, means for connecting the central portion of the cylinder between said pistons and'said connected end portions of the cylinder, with said pressure, including a single reversing valve mechanism constructed to maintain said PiS" tons in a balanced condition when the reversing valve mechanism is in an interjacent position between its limits of movement, an operator operated part connected with'said valve mechanism, brake mechanisms for the steering wheels of the vehicle connected with one of said pistons, brake mechanisms for non-steering wheels of the vehicle connected to the other of said pistons, said valve mechanism comprising a'valve. casing and a valve actuating part movable relatively to the casing, one of said relatively movable parts.

being connected to the piston connected with the nonsteering wheel brake mechanisms, and the other being connected to said-operator operated part, and means for limiting the relative movement of said relatively movable parts, to enable the operator to apply his physical force to the brake mechanisms for the non-steering wheels, in addition to the suction passage and with a source of higher power of the actuator or in case of failure of power.

33. In an automotive vehicle provided with an internal combustion engine having a throttle controlled suction passage, the combination of-a power actuator comprising a cylinder closed at each end, two pistons movable independently of each other, in both directions in said cylinder, said cylinder being provided with a communicating passage connecting the opposite end portions of the cylinder on the outer faces of the pistons, means for connecting the central portion of the cylinder between said pistons and the said connected end portions of the cylinder, with said suction passage and with a source of higher pressure including a single reversing valve mechanism located inone of said pistons and constructed to maintain said pistons in a balanced condition when the valve mechanism is in an interjacent position between its limits of movement, brake mechanism for the non-steering wheels of the vehicle connected with the iston containing said valve mechanism, bra e mechanism for the steering wheels of the vehicle connected with the other of said pistons, an operator operated part, said valve mechanism comprising a valvecasing and a valve actuating part movable relatively to the casing, one of said relatively movable parts being connected to the piston containing the valve'mechanism and the other being connected to said operator operated part, and means for limiting the relative movement of said relatively movable parts, to enable the operator to apply his physical force to the brake mechanisms for the non-steering wheels in addition to the power of the actuator or in case of failure of power.

34. The combination of a power actuator comprising a cylinder closed at each end, two pistons movable independently of each other in both directions in said cylinder, the said cylinder being provided with a communieating passage connecting the opposite end portions of the cylinder on the outer faces of the pistons, means for establishing differential pressures within the central portion of the cylinder between said pistons and within said connected end portions, including a single throttling and reversing valve mechanism located in one of said pistons and constructed to maintain said pistons in a balanced condition when the reversing valve-mechanism is in an interjacent position between its limits of movement, an operator operated part connected with said valve mechanism, and being also connected with the piston containing said valve mechanism by means providing lost motion, and brake mechanism operatively connected with said pistons.

35. The combination of a power actuator comprising a cylinder closed at each end, two pistons movable independently of each other to maintain said pistons in a balanced condi-v tion when the reversing valve mechanism is in an interjacent position between its limits I of movement, an operator operated part connected with said valve mechanism, and being also connected with the piston containing said valve mechanism by means providing lost motion, brake mechanism operatively connected with one of said pistons, and sepa rate brake mechanism operatively-connected with the'other of said pistons.

36. In an automative vehicle, the combination with a plurality of independently operable brake mechanisms, power operated means for said brake mechanisms, a sin le controlling valve mechanism therefor or applying all of said brake mechanisms by power, said valve mechanism bein with certain of said independent y operable brake mechanisms less than the whole number, and an operator operated part connected with said valve mechanism, whereby the operator can apply his physical force to the brake mechanism connected with said valve mechanism in addition to the force applied thereto by said power operated means, or to apply said brake mechanisms so connected with the operator operated part by physical force alone in case of failure of power.

37. In an automotive vehicle provided with an internal combustion engine having a suc-' tion passage, the combination with a plurality of independently operable brake mechanisms, power operated jmeans for operatin all of said brake mechanisms, means inclu ing asingle controlling valve mechanism for placing said power operating means in communication with said suction passage and with the atmosphere under the control of said valve mechanism, connections between said valve mechanism and certain of said brake mechanisms less than thewhole number, and

an operator operated part connected with said valve mechanism, whereby the operator can apply his physical force throu h said valve mechanism to said brake mec anisms connected therewith in additionto the power exerted thereon by the power operated means, and can apply said brake mechanisms so connected with the operator operated part by physical force alone in case of failure of power.

38. The combination with a power actuator including a cylinder and a piston movable therein and means for connecting the actuasures, includin tor with sources of higher and lower presa controlling valve mechanism, means or connecting said actuator with independently operable brake mechanisms for a plurality of pairs of wheels of a vehicle for operating all of the brake mechanisms of said vehicle by power under the control of said valve mechanism, an operator operated part operatively connected to certain of said brake mechanisms less than the whole number operatively connected with the actuator, said; valve mechanism being operatively connected with said operator operated part and a part moving with the piston of the actuator and controlled by both.

' 39. In an automotive vehicle, the combination with a plurality of independently operable brake mechanisms, power operated means for operating all of said brake mechanisms, a single controlling valve mechanism for said power operated means, an operator operated part, a connection therefrom to certain of said brake mechanisms less than the whole number and including a provision for lost motion, means directly actuated by said connection for operating said valve mechanism, whereby the operator can apply all of the brakes by the power operated means or apply his physical force to said certain brake mechanism in addition to the power exerted thereon by the power operated means and can operate said certain brake mechanism by his physical force alone in case of failure of CALEB S. BRAGG. VICTOR W. KLIESRATH.

power. 

